afio - utility to copy or restore files to an archive file. This utility is not part of the basic internal and external programs under Red Hat Linux. It is available as an rpm on the rpmfind.net site.

agetty - enables login on terminals. See getty, mgetty, and uugetty.

ali - list mail aliases

alias - assign name to specified command list. This is actually a shell builtin. On my Red Hat system, I have global alias commands in my /etc/bashrc file and in my /.bashrc file. On my Slackware box, I have made the rm command a little bit safer with

alias rm='rm -i'

so that you can't recursively delete your /dev directory without telling the system you're sure you want to do it.

apsfilter - printer filter called by lpd to deal with printing different types of files. This is a fairly sophisticated print filter. It is not set up by default in Slackware. It used to be available on the second cd of a Slackware distribution. Since 4.0, it is available as one of the main packages in the ap set. Read the mail that the installation program sends to the root user. I believe that Red Hat uses its own printer filters.

ar - create, modify and extract from archives

arch - print machine architecture type

as - the portable GNU assembler

asapm - AfterStep laptop advanced power management utility

ash - a shell, a very simple shell program sometimes used on boot diskettes since it takes up much less space than bash, tcsh, zsh, etc.

asload - AfterStep cpu load monitor

asmail - AfterStep mail checking utility

asmodem - AfterStep utility to monitor modem status

aspell - a spell checking program along the lines of ispell

aspostit - X Window postit note utility

at - executes a shell script at specified time. Use atq to show pending jobs, and atrm to remove jobs from the queue.

cd - change working directory. This is a shell builtin in bash, tcsh and zsh.

cdplay - command line utility for playing audio cds

cfdisk - similar to fdisk, but menu-driven

chat - used to interact with a modem via a chat script

chgrp - changes group associated with file. Can be used to change the group associated with subdirectories and files of a directory.

usage: chgrp group files

or: chgrp -R group files

chkconfig - Query or update system services/daemons for different runlevels. Manipulates the various symbolic links in /etc/rc.d. This utility is included with many rpm-based distributions such as RedHat and Mandrake. It is designed to work with System V initialization scripts. Graphical tools for configuring system services include ntsysv, tksysv and ksysv (the latter is a KDE utility).

chmod - set permissions (modes) of files or directories. A value of 4 is used for read permission. A value of 2 is used for write permission. A value of 1 is used for execute permission. See umask for default file permissions upon file creation. Chmod can also be used to change the suid bit on files. The syntax for the symbolic version is

chmod [options] who operation permission file-list

The syntax for the absolute version is

chmod [options] mode file-list

To set the uid to the owner's permissions, use

chmod u +s file-name

To set the uid to the group's permissions, use

chmod g +s file-name

There are lots of security issues related to allowing a program to have root's permissions when run by an ordinary user. I don't pretend to understand all of these issues.

chown - changes ownership of a file. Can be used recursively.

usage: chown userid files

or: chown -R userid files

chsh - change default shell

ci - creates or records changes in an RCS file

clear - clear screen command

cmp - compares two files for differences

usage: cmp file1 file2

co - retrieves an unencoded version of an RCS file

comm - compares sorted files

configure - automatically configures software source code

color-xterm - color xterm program. Under Red Hat, this is just a link to xterm-color.

control-panel - graphical system configuration tool under Red Hat.

cp - copies on or more files. Recursive copying is one simple way of archiving part of a directory structure. Use the command as follows:

cp -r /sourcedirectory /targetdirectory

cpio - direct copy of files to an output device. Allows creation of archive file spanning multiple diskettes. Allows one directory structure to be mirrored elsewhere on the partition or on another partition. In order to back up an entire directory structure on diskettes, cd to the directory and use the following command:

find . -depth -print | cpio -ov > /dev/fd0

To restore from diskettes, use:

cpio -iv < /dev/fd0

The cpio command will prompt the user to insert more diskettes as they are needed. The command for mirroring a directory structure is the following:

find . -depth -print | cpio -pv /destinationdirectory

This copies the working directory and its contents, including subdirectories, into /destinationdirectory. In order to copy an individual file which is larger than a floppy, use:

find . -name nameoffile -print | cpio -iv > /dev/fd0

cpkgtool - Slackware tool to install, uninstall and query packages. Front end to installpkg, removepkg, makepkg. This is the graphical version that uses ncurses.

cpp - GNU C-compatible compiler preprocessor

crontab - schedules command to run at regularly specified time

csh - run C shell

csplit - separate files into sections. See also split.

cvs - manages concurrent acces to files in a hierarchy. Stands for concurrent version system. Is built on RCS. It stores successive revisions of files efficiently and ensures that access to files by multiple developers is done in a controlled manner. Useful when many developers are working on the same project.

cut - selects characters or TAB-separated fields from lines of input and writes them to standard output

date - displays or sets date and time

usage: date

or: date date

dd - direct copy of file from one device to another. Can be used to make copies of boot or root diskettes for installing Linux. It can be used, for example, to make and exact copy of a floppy disk, as follows. First, place the diskette to be copied in the floppy drive. Then,

dd if=/dev/fd0 ibs=512 > floppy.copy

Replace the diskette with a fresh diskette.

dd if=floppy.copy bs=512 of=/dev/fd0

The ibs and bs options specify the block sizes for input and for both input and output. A boot disk image can be directly copied to a floppy using the second of the two dd commands above.

declare - declares attributes for a variable (same as typeset). This is a shell builtin.

df - displays capacity and free capacity on different physical devices such as hard drive partitions and floppy drives that are mounted on the file system. Gives free space in blocks. With the (undocumented) option -h, the program gives free space in Mb or Gb. This is useful for those accustomed to thinking of the capacity of a high-density 3.5 inch diskette as 1440k.

diff - displays differences between two files

usage: diff file1 file2

diff3 - compares three files and reports on differences

dip - used to set up a SLIP or PPP connection. It can be used to set up an outgoing SLIP connection or an incoming connection.

diplogin - used for setting up incoming dip connections. See the man page for dip.

dir - a variation of the GNU ls command that defaults to printing file names in columns

dircolors - set colors for GNU ls command. In Slackware, this command is run by the /etc/profile script. Then, whenever xterm is run with the -ls (login shell) option, ls displays different colors for different types of files. Typical usage is eval `dircolors -b`. In Red Hat and Mandrake, I get color directories by aliasing the ls command (see below).

display - set display for output of programs under X Window. Can be used to run a program on a remote machine while displaying the output on a local machine. The remote machine must have permission to send output to the local machine. This is actually an environment variable. See the more detailed discussion in connection with the xhost command below.

dmesg - displays messages from /var/log relative to the most recent boot

dos - invoke the DOSEMU DOS emulator

du - displays information on disk usage. The command

du / -bh | less

will display detailed disk usage for each subdirectory starting at root, giving files sizes in bytes.

dvilj - send a dvi file to a Laserjet printer. There are specialized versions for individual models of Laserjet printer.

dvilj2p - specialized version of dvilj for the IIp series of printers. See above.

dvips - send a dvi file to a Postscript printer, to a Postscript capable Laserjet printer, or to a file (with the -o option). There is a switch to print only a subset of the pages, and another switch to print in landscape mode. Use -t landscape, which is one of the arguments to the paper type switch. If you have one page of a document that is a wide table, and you wish to print this in landscape mode, use

dvips filename -pp pagenumber -t landscape

e2fsck - check an ext2 filesystem. The syntax is

e2fsck /dev/devicename

where the filesystem is on /dev/devicename. The device should not be mounted, and this program must be run as root.

echo - write arguments to standard output. One use is to print out information about environment variables, as in

env - desplay the current environment or set a variable equal to a new value

eval - scans and evaluates the command line. See dircolors command. This is a shell builtin.

ex - interactive command-based editor. The man page lists it as being the same as vim, an improved version of vi.

exec - system call which creates a subshell to execute a binary or a script. This is a shell builtin.

execve - a variation of the exec command.

exit - exit a shell. This is a shell builtin.

expand - convert tabs in files to spaces and write to standard output

expect - a program that ``talks'' to other interactive programs according to a script. Following the script, Expect knows what can be expected from a program and what the correct response should be. An interpreted language provides branching and high-level control structures to direct the dialogue. In addition, the user can take control and interact directly when desired, afterward returning control to the script.

export - place the value of a variable in the calling environment (makes it global). This is a shell builtin.

expr - utility evaluates an expression and displays the result

f2c - FORTRAN to C translator

f77 - FORTRAN 77 compiler

false - null command that returns an unsuccessful exit status

fax - simple user interface to efax and efix programs

fc - views, edits, and executes commands for the history list. This is a shell builtin.

fdformat - low level format of a floppy device

fetchmail - retrieve mail from a remote mail server and pass it to local SMTP agents on the local machine

fdisk - used to partition hard drives

usage: fdisk device

fg PID - bring a background or stopped process with pid ``PID'' to the foreground. This is a shell builtin. If only one process is running in background mode, fg with no argument is sufficient to bring it to the foreground

fgrep - search for patterns in files

file - displays classification of a file or files according to the type of data they contain

find - find files according to a large variety of search criteria. The find command that I use the most is

find . -name filename -print

in order to find files matching a particular name on the working directory and all subdirectories. Find can be incredibly powerful, but it is incredibly obscure.

finger - display information about a specified userid or userids

fmt - simple text formatting utility. Tries to make all nonblank lines nearly the same length.

fold - break lines of specified files so they are no wider than a specified lengths

fortune - available in the bsdgames package in Slackware and other distributions. Put a call to fortune in /etc/profile and get something inspirational or amusing every time you fire up an xterm as a login shell.

free - gives used and free memory on system along with other useful information

fromdos - takes a DOS text file from stdin and sends a Unix file to stdout.

fsck - file system check and repair

ftp - file transfer over network

g++ - C++ compiler

g77 - GNU Fortran 77 compiler

gawk - GNU awk, mostly for processing delimited text files

gcc - invoke C, C++ compiler

getipts - parses arguments to a shell script. This is a shell builtin.

getkeycodes - print kernel's scancode-to-keycode mapping table

ghostscript - set of printing utilities. It seems to be obligatory to have this if a TEX installation such as teTEX is installed. How they communicate with one another is somewhat obscure.

grep - used to find a string within a file. The -i option returns matches without regard to case. The -n option means that each line of output is preceded by file name and line number. The -v option causes non-matched lines to be printed.

usage: grep pattern files

or: grep -i pattern files

or: grep -n pattern files

or: grep -v pattern files

groupadd - create a new group on the system

groups - shows which groups you are in

grub - Gnu grand unified bootloader. Can be used instead of lilo to boot multiple operating systems. I encountered a couple of snafus trying to install grub on my home machine after installing Mandrake 8.0 and choosing the lilo bootloader during the initial install. The Mandrake installation program set up /boot/vmlinuz as a symlink to the actual kernel, vmlinuz-2.4.3-20mdk. It took me a while to figure out that grub doesn't understand symbolic links. The documentation suggests installing grub on a diskette using the ``dd'' command. This refused to work, but

grub-install '(fd0)'

did work. The single quotes are necessary. The files necessary to run grub are normally located in /boot/grub. Once the file menu.lst has been edited and appropriated entries added to boot the different operating systems on one's hard disk(s), the following sequence of commands can be used to install grub in the master boot record (MBR) sector of the hard disk:

root (hd0,x)

setup (hd0)

Here, the x should be replaced by the partition where the /boot/grub directory is located, which is probably the root partition of the Linux system. Note that grub has its own conventions for naming devices and numbering partitions, so that for example a partition which is called hda6 under Linux will be called (hd0,5) by grub.

hash - remembers the location of commands in the search path. This is a shell builtin.

head - displays first part of a file

history - command for viewing and manipulating the shell command history list

host - look up host names using domain server

hostname - used to get or set hostname. Typically, the host name is stored in the file /etc/HOSTNAME.

hwclock - used to query and set the hardware clock

hylafax - commercial fax program

id - display userid and groupid

inetd - daemon which starts up other daemons on demand. Configured in /etc/inetd.conf.

ifconfig - display (as root) information on network interfaces that are currently active. First ethernet interface should be listed as eth0, second as eth1, etc. First modem ppp connection should be listed as ppp0, etc. The ``lo'' connection is ``loopback'' only.

ifdown - shut down the network interface

ifup [interface_name] - start up the interface

info - display system information. This is the GNU hypertext reader.

init - the mother of all processes, run at bootup, executes commands in /etc/inittab. Can be used (with root privileges) to change the system run level.

usage: init run_level

insmod - used (by root) to install modular device drivers

installpkg - Slackware command to install one of the packages from the program sets

jobs - displays list of current jobs in the background. This is a shell builtin.

joe - simple WordStar-like text editor. It can be invoked in emacs emulation mode with jemacs and in WordStar emulation mode with jstar.

jove - Joseph's Own Version of Emacs. A simple emacs clone.

kbd_mode - print current keyboard mode

kernelcfg - GUI to add/remove kernel modules (as root in X terminal).

kerneld - kernel daemon, a process that stays in memory and does all sorts of useful stuff, like automatic loading of device driver modules

kikbd - a utility program that comes with KDE that allows users to switch on the fly among different international keyboards. It can be used under different window managers than kfm.

kill - sends a signal to (especially to terminate) a job or process. This is a shell builtin in bash, tcsh and zsh.

killall - kill processes by name. Kill all processes which are instances of the speciffied program. Also used to send signals to processes or restart them.

killall5 - kill all processes except the ones on which it depends

last - generate a listing of user logins

lastlog - prints the last login times of all users

latex - compile a LATEX file

ldconfig - creates the necessary links and cache (for use by the run-time linker, ld.so) to the most recent shared libraries found in the directories specified on the command line, in the file /etc/ld.so.conf, and in the trusted directories (/usr/lib and /lib). Ldconfig checks the header and file names of the libraries it encounters when determining which versions should have their links updated. Ldconfig ignores symbolic links when scanning for libraries.

ldd - list the shared libraries on which a given executable depends, and where they are located

leave - display reminder at specified time

less - Linux alternative to ``more'' command. Displays text files, one screenful at a time. When less pauses, there is a large number of available commands to tell it what to do next. One can scroll both forwards and backwards.

let - evaluates a numeric expression. This is a shell builtin.

lilo - installs boot loader on the boot sector of a hard drive, of a diskette, or in another location. My 486 has a hard drive that is too large for the machine's BIOS, so I have to boot from a floppy. To create a boot diskette, I do the following (as root):

/sbin/fdformat /dev/fd0H1440

/sbin/mkfs.ext2 /dev/fd0

mount -t ext2 /dev/fd0 /mnt/floppy

cp -dp /boot/* /mnt/floppy

/sbin/lilo -C /etc/lilo.flop

The -C option to lilo has lilo use the lilo.flop file instead of the default lilo.conf.

linuxconf - interactive tool for configuring Linux system. Uses X if loaded. This is a Gnome tool. It comes with my Red Hat distribution, and is not included with Slackware. It would seem to be the easiest way to configure Linux under Slackware. Version 1.15 is available for Slackware. There is a pretty good introduction to the use of linuxconf in the Red Hat 5.2 installation manual, which is available online at their web site.

ln - creates a link to a file. Used to create hard links and, with the -s option, symbolic links which can link files on different disk partitions. The syntax is

ln [options] source [dest]

locate filename - find the file name which contains the string ``filename''. The syntax is easier than the find command.

will give directory listings in color, with file sizes in kilobytes, and append a character to the file to indicate its type.

lsattr - list attributes of files in ext2 file system

lsmod - used (by root) to show kernel modules currently loaded

lspci - utility to display information on pci buses and hardware devices attached to them. Part of the pciutils package that comes with many Linux distributions.

lspnp - utility to display information about pnp devices. Part of the pcmcia or kernel-pcmcia package, depending on the distribution.

m4 - an implementation of the traditional Unix macro processor. It can be used with the sendmail configuration package in Red Hat (and Slackware) to generate a sendmail.conf configuration file without having to edit the configuration file directly.

magicfilter - general purpose printer filter. See apsfilter above. apsfilter is the printer filter that comes with the Red Hat and Slackware distributions.

mail - sends or reads electronic mail

make - keeps a set of programs current. This is a utility that helps when developing a set of programs. It works by executing a script called makefile, Makefile or GNUmakefile in the working directory. It is very often used in combination with configure when compiling and installing noncompiled software packages.

makebootdisk - command in Slackware to do just what the name says

MAKEDEV - executable script to make device files on /dev

makeswap - configures swap space

man - displays information from online Unix reference manual

manpath - attempt to determine path to manual pages

mc - Midnight Commander file manager and visual shell

mesg - enables/disables reception of messages

minicom - terminal program

mkdir - create a directory

mkfs - create a file system (format) on a device or partition. Should be invoked after lowlevel formatting of the disk using fdformat. It has several versions which are all links to the basic program, such as mkfs.ext2 and mkfs.msdos.

mpage - print multiple pages per sheet on a Postscript printer. Can also be used to print a page in landscape mode.

Mtools - package of MS-DOS utilities. Includes the following commands.

mcd - changes working directory on DOS disk

mcopy - copies DOS files from one directory to another

mdel - deletes DOS files

mdir - lists contents of DOS directories

mformat - adds DOS formatting information to a disk

mtype - displays contents of a DOS file

The default device for execution of these commands is /dev/fd0 and can be referred to as ``a:''.

mv - moves (renames) files

netconf - used (as root) to set up network

newaliases - rebuilds the /etc/aliases database used by sendmail. Must be rerun every time /etc/aliases is modified for the changes to take effect.

newgrp - similar to login. Changes user's identification

nice program_name - sets the priority of the program ``program_name''.

nm - lists the symbols from object files objfile. If no object files are given as arguments, nm assumes `a.out'.

nohup - runs a command that keeps running after logout. The command is in principle immune to hangups, and must have output to a non tty. According to Linux in a Nutshell, this is necessary only in the Bourne shell, since modern shells preserve background processes by default.

ntsysv - run level editor under Red Hat. This is the equivalent of tksysv, but does not require a graphical interface.

nxterm - color xterm program. The man page for nxterm under Red Hat brings up the same page as xterm.

od - dumps contents of a file

passwd - change login password

paste - joins corresponding lines from files

patch - updates source code. Attempts to update a file from a file of change information, or pathces, created by diff.

pathchk - determine validity and portability of filenames

pdflatex - part of the pdftex program suite. Produces pdf output from a LATEX file.

pdftex - produces pdf output from a TeX file. See also pdflatex. This program is part of the tetex 0.9 distribution that is included with Red Hat 5.2 and above, and with Slackware 4.0 and above. It is also available as a separate program.

perl - practical extraction and report language

pg - display data one screenful at a time

pico - simple screen oriented text editor. It is included as part of the Pine program.

ping - check if Internet computer is responding. Can also measure the time it takes the queried computer to respond.

pkgtool - Slackware tool to install, uninstall and query packages. Front end to installpkg, removepkg, makepkg. The cpkgtool is the ncurses graphical version of this program.

rpm - invokes the Red Hat package manager in command line mode. I often use this command in query mode to query packages about what files they contain and to find out which package owns a particular file. Examples are

rwho - show who is logged in on a LAN. The rwho service must be enabled for this command to run. If it isn't, run ``setup'' as root. I don't understand this last remark, which comes from ``Linux Newbie Administrator Guide''.

rxvt - a terminal program similar to xterm, but which has less features and uses less memory

set - set or display value of shell variables. This is a shell builtin. The command

set | less

prints the current user environment, giving the values of currently defined variables.

setenv - set or display value of environment variables

setserial - used by root to configure a serial port

setterm - set terminal attributes for a virtual console

setuid - set the id of a program when it is run. Used, for example, to give root privileges to a program run by an ordinary user. This is actually done by running the chmod program as root. See the chmod command for the syntax.

setup - Slackware program to set up program sets and configure system. Setup devices and file systems, mount root file system

sh - standard Unix shell. On Linux, just another name for bash.

shift - promotes each command-line argument. This is a shell builtin.

showmount - show information about an nfs server

shutdown - reboot or shut down system as root, after specified amount of time. With the -r option, reboot. With the -h option, halt the system.

type - displays how each argument would be interpreted as a command. This is a shell builtin.

typeset - declares attributes for a variaable (same as declare). This is a shell builtin.

ul - translate underscores to underlining

umask - establishes the file-creation permissions mask. Usage is

umask xyz

The system subtracts x, y and z from the owner, group and other file permissions that it would otherwise assign to new files. This is a shell builtin.

umount [device] - finish writing to the device and remove it from the active filesystem. The command umount -a will (re)mount all file systems listed in /etc/fstab.

unalias - remove name previously defined by alias. This is a shell builtin.

uname - displays information about the system. With no arguments, it displays the name of the operating system. With the -a option, it displays information about the operating system, the host name, and hardware.

wait - waits for a background process to terminate. This is a shell builtin.

wc - displays number of lines, characters and words in a file

Wharf - the AfterStep application dock module

whatis - display one-line summary of specified command

whereis - use to find utilities in standard locations

which - used to find utilities in search path. Will return the absolute directory path of the named utility program.

who - display information about currently logged in userids

whoami - display information about userid that is currently logged in

wish - front end to tk, an X window extension of tcl

workbone - console based cd player

workman - graphical cd player program

write - send messages to another local user

X - the X server

xadm - display advanced power management BIOS information

xargs - converts standard output of one command into arguments for another. This is one of those powerful but obscure commands. Xargs reads arguments from the standard input, delimited by blanks (which can be protected with double or single quotes or a backslash) or newlines, and executes the command (default is /bin/echo) one or more times with any initial-arguments followed by arguments read from standard input. Blank lines on the standard input are ignored.

xbiff - graphical mail delivery notification utility

xcalc - simple calculator program

xclipboard - name says it all

Xconfigurator - Red Hat utility for configuring settings for X

xdm - used to start an X login session. This can be used to start a login session on a remote system. See the discussion on the following site:

See the man pages for X, xdm, and Xserver. As usual, the man pages are pretty obscure. The best single source seems to be the Xserver man pages. After X is configured, X needs to be started at bootup with the command (in /etc/rc.d/init.d/xterm):

X -quiet -query remotemachineaddress

If the address of a nameserver is not configured, then the numeric address of the remote machine rather than its name should be entered. If the machines are connected through ethernet cards and the net, then obviously basic networking has to be set up. Gnome and KDE come with their own versions of X display/login managers, called respectively gdm and kdm.

xdvi - view a dvi file compiled under LATEX

xedit - a simple text editor for X

xf86config - graphical configuration tool for X

XF86Setup - graphical configuration tool for X

xfd - display an available font in X. Creates a grid in an x-term with one character per rectangle.

xfig - utility for interactive generation of figures

xfm - graphical file manager for X

xhost - tell X server that remote computer has access to your machine and that you will use the remote computer. This can be used to set up remote X sessions. To set up a remote X session on the UQAM Nobel machine, run the following command on the local machine (one doesn't have to be root to do this)

xhost +nobel.si.uqam.ca

Then, log onto the remote machine using rlogin (see above) or telnet. Once logged in, use the following command to get the remote X server to open an X terminal on the local machine:

setenv DISPLAY localhostname:0 ; xterm &

This is valid for csh, which is the default login shell on Nobel. For ksh, (and I think bash) replace with

DISPLAY=localhostname:0

export DISPLAY ; xterm

Other X-based programs such as Netscape or Gauss (graphical version) can also be run on a remote machine with display on the local machine with little trouble. The local X server is the program that has all of the information concerning the properties of the graphics card and terminal, so it must be necessary to have X running on the local machine. The following should also work. After using xhost to give permission to the remote machine to display on the local machine, use

netscape -display localhostname:0.0

Question: can one start the X session on the local machine and then run a remote copy of a window manager?

xinit - start X Window. The command startx is a front end to xinit in Linux, including Slackware.

xload - displays a graphic of the system load

xlpq - graphical interface to print manager. This is included on one of the XFCE menus, but does not seem to be a part of the base Red Hat distribution.

xlsfonts - list fonts available under the X Window system.

xman - browsable command reference. Displays manual pages under X.

xmh - graphical front end under X to the nmh mail handling system. This program is part of the XFree86 package in Red Hat.

xmodmap - utility for modifying keymaps and pointer button mappings in X. Can be used to install a French Canadian keyboard. Download the Xmodmap.cf file from www.linux-quebec.org, and insert the command